Kevin Pietersen has long flouted conventional wisdom in a career that has taken him to within one match of playing 100 Tests for England. Such an approach may help explain his success on the field and problems off it.

Born and raised in South Africa, but with an English mother, there are those who contend the outspoken Pietersen, 33, is playing for the wrong country.

Moreover his reason for shunning South Africa -- frustration that a post-apartheid quota policy was harming his prospects -- touched a nerve.

Equally, there are plenty of others who say Pietersen was not the first young sportsman to make a pragmatic choice, and that any doubts are more than offset by his impressive Test record of nearly 8,000 runs at an average of more than 48, with 23 hundreds.

For the most part, during what has been a largely successful time for England, that latter viewpoint has been the one held by the selectors.

Certainly, the superlative quality of several of his innings is beyond question.

His maiden Test century was an audacious counter-assault against an attack including Glenn McGrath, Brett Lee and Shane Warne that saw England wrest back the Ashes in 2005.

And in Mumbai last year, he made 186 against India on a spinners' pitch where most batsmen were struggling just to stay at the crease.

That South Africa, who classed him as an off-spinner who batted, didn't quite realise what they had may have been down to Pietersen's departures from orthodoxy.

An initial overly-long stride forward, and an ability to whip off-stump deliveries through midwicket, are not in the coaching manual.

And few players as talented as Pietersen can look so nervous and uncertain in the early stages of an innings.

Yet the combination of will, a fantastic eye, skill and a 6ft 4in frame all allow him to play shots few others can match.

England's desire to have a captain across all three formats saw Pietersen given the job in 2008, and it might have been the making of an outsider trying to fit in.

But after a falling-out with coach Peter Moores, Pietersen's tenure lasted barely five months before both men lost their posts.

Last year's Headingley Test against South Africa encapsulated the rollercoaster England career of Pietersen.

Having produced a match-saving century where Dale Steyn and Morne Morkel were treated like club bowlers, Pietersen gave an equally stunning post-match press conference.

"The saddest part about all this is that the spectators just love watching me play and I love playing for England," he declared.

"But the politics is what I have to deal with personally and it's tough being me in this dressing room. Playing for England is tough. We'll see."

These comments chimed with the idea of Pietersen the mercenary, after he clashed with England's management over his desire to play more lucrative Twenty20 cricket abroad.

Soon afterwards it emerged he'd sent "provocative" texts allegedly critical of then England captain Andrew Strauss to South African players.

Pietersen was briefly dropped by England, only to be recalled when Alastair Cook took over following Strauss's retirement.

In short, Pietersen -- who averages nearly 50 against Australia -- can be difficult, but is worth the trouble.

Now the question is whether there's any more trouble to come in the later stages of his international career.